Missile guidance systems using radar to track a metal target and to guide the missile towards the metal target are well known. In a typical guidance system, the target is illuminated with radar signals (electromagnetic radiation at a radio frequency). Reflected signals from the target are detected by the guidance system and used to determine the direction of the target, the distance to the target and/or the movement of the target. Although such conventional systems have performed adequately, they are subject to interference from radar signals reflected from objects other than the target. Natural background backscatter or surface clutter results from radar signals being reflected from objects such as foilage, earth, sea waves or other objects capable of reflecting radar signals. In order to achieve desired performance characteristics, a guidance system for a missile should be able to detect and track a target even in the presence of surface clutter or background backscatter. The ability of a missile guidance system to distinguish the target from background backscatter is particularly important during a terminal encounter when the missile is in close proximity to the target.
Thus, a need has arisen for a missile guidance system capable of tracking a metal target when illuminated by radar signals when the target is obscured by background backscatter. In particular, a need has arisen for a guidance system capable of guiding a missile during a terminal encounter with a target which is illuminated with radar signals and is obscured by the presence of natural background backscatter.